Let me see if I can clarify for you then.
The dual receiver mode allows you to point to the 72.7 satellite and both receivers can watch any programming on any channel without issue. However, there is NO Network programming on 72.7.
You can still use 2 receivers with the X2 in the non-dual receiver mode but just like any other dome antenna the master receiver will determine which satellite the antenna is pointed to. So, as long as both receivers are watching programming from the same satellite there are no issues. Most of the HD programming comes from the 129 satellite for the WA so as long as you are both HD fans there is not likely to be any conflicts.